Process for preparing ortho-aminophenol-beta-hydroxyethylsulfone sulfuric acid esters



United States Patent PRQCESS FOR PREPARING ORTHQ-AP/ILYQPET- NOL (3 HYDROXYE'IHYLSULFONE SULFURIC ACID ESTERS Ernst Hoyer, Frankfurt am Main, and Walter Noll, Bad Soden, Taunus, Germany, assignors to Farbwerke Hoechst Aktiengeselischaft vormals Meister Lucius 3: Briining, Frankfurt am Main, Germany, a corporation of Germany No Drawing. Filed Oct. 3, 1961, Ser. No. 142,528

Claims priority, application Germany Oct. 6, 1960 4 Claims. (Cl. 260-457) It is known that ortho-aminophenol-B-hydroxyethyL sulfone sulfuric acid esters of the formula S!OQCHZCHQOSO3H in which R represents a hydrogen atom or a nitro group, can be prepared by esterifying the corresponding orthoarninophenol-B-hydroxyethylsulfones of the formula S OrCHgCHzOH in which R has the meaning given above, in an excess of sulfuric acid of high concentration at a temperature ranging for example from 30 C. to 35 C. (cf. German Patent 93 8, 145

Prior to the esterification in sulfuric acid, however, this process requires a separation and drying operation of the ortho-aminophenol-fi-hydroxyethylsulfones which in many cases, due to the extremely high solubility in water of many of these substances and their liability to decompose relatively easily may involve considerable losses in yield.

Now we have found that by treating fi-hydroxyethylsulfonylbenzoxazolones of the general formula in which R represents a hydrogen or halogen atom, an alkyl, amino or nitro group, with highly concentrated sulfuric acid, preferably of 85% to 95% strength, at a raised temperature, suitably between about 110 C. and 160 C., there are obtained in an excellent yield the corresponding ortho-aminophenol-B -hydroxyethylsulfone sulfuric acid esters of the general formula in which R has the meaning given above. The new process differs advantageously from that described in German Patent 938,145 in that the separation of the free ortho-aminophenol-[i-hydroxyethylsulfones is not necessary. The fifhydroxyethyl-sulfonyl-benzoxazolones used as starting materials are distinguished from the ortho- 3,135,779 Patented June 2, 1964 aminophenol-[i-hydroxyethylsulfones by their substantially lower solubility in cold aqueous media and their considerably lower sensitiveness to oxidation by which the losses in yield occurring at the isolation of the free orthoaminophenol 5 hydroxyethylsulfones can largely be avoided. The new process, therefore, represents a considerable technical advance.

The ortho-aminophenol-{i-hydroxyethylsulfone sulfuric acid esters which can be prepared by the process of the present invention are obtained with a very good yield in aqueous solution. In some cases they can also be separated in solid form with a good yield.

The B-hydroxyethylsulfonyl-benzoxazolones used as starting products in the process of the present invention can, for instance, be prepared by reducing ortho-nitrophenol-fi-hydroxyethylsulfones which may contain substituents and reacting the alkaline reaction mixtures with phosgene, or by reducing benzoxazolone-sulfochlorides which may contain substituents to obtain the corresponding sulfinic acids and reacting these compounds, for example, with B-chloroethyl alcohol. The benzoxazolones can also be prepared by demethylating ortho-anisidine-B- hydroxyethylsulfones which may be substituted and reacting the dissolved ortho-aminophenol s-hydroxyethylsuL tones with phosgene. Furthermore, arninobenzoxazolone-B-hydroxyethylsulfones can be prepared by catalytic reduction of the corresponding nitrobenzoxazolone-fi-hydroxyethylsulfones.

The ortho-aminophenol-B-hydroxyethylsulfone sulfuric acid esters obtainable by the process of the present invention can be used for the manufacture of dyestuifs, particularly metallizable azo-dyestuifs, by diazotization and coupling with suitable coupling components.

The following examples serve to illustrate the invention but they are not intended to limit it thereto, the parts being by weight unless otherwise stated, and the relationship of parts by weight to parts by volume being the same as that of the kilogram to the liter.

EXAMPLE 1 48.6 parts of S-(fi-hydroxyethylsulfonyl)-benzoxazolone melting at 184 C. and corresponding to the formula are introduced, at a temperature ranging from 70 C. to C., into parts of sulfuric acid of 90% strength and stirred first for 90 minutes at a temperature within the range of C. to C. and then for 30 minutes at a temperature ranging from 153 .C. to 156C. After cooling, the reaction mixture is poured onto 400 parts of ice, and a solution of 108 parts of sodium carbonate in 360 parts by volume of water is added dropwise at a temperature ranging from 0 C. to 5 C. The mixture is then rendered neutral by introducing 21 parts of whitening and filtered at 15 C.

The clear neutral solution contains 57.9 parts of 2- aminophenol-4-fi-hydroxyethylsulfone sulfuric acid ester;

are used, there are obtained the corresponding orthoaminophenol-fl-hydroxyethylsulfone sulfuric acid esters the yields of which are indicated in the lastcolumn of the table.

Quantity i Yieldin used D1 B41ydroxyethylsulfonylbenz- Melting point percent parts by oxnzolone of the formula of the weight theory 57.6 02N NH 244 o; to 246 0. (with decomso position).

I SOs-CHs-CHzOH 51.6 HEN NH 240 0. (with decomposition) 97.

Iv SO2CH2CH2OH NH-CO 4s.s- 0 205 C 93 l SO2CHzCHzOH NH-O o I l 55.5 0 218 0 96 SOz-CHr-CHzOH 64.4 Br NE 253 0. to 254 0 97 I r SOz-CH2CH2OH nH -c 0 I V V SOzCHnCH2OH EXAMPLE 2 V 48.6,parts of 6- (fi hydroxyethylsulfonyl) -benzoxazo1one melting at 205 C. are introduced, 'at a temperature ranging from C. to G, into parts of sulfuric acid of 90% strength and the Whole is stirred for 5 hours at a temperature ranging from C. to C. After cooling, .the mixture is poured onto 400 parts of ice. The

sulfuric acid solution obtained; contains 54.9 parts of.2- aminophenol-S-fl-hydroxyethylsulfone sulfuric acid ester which. corresponds to 92.5% of the. theoretical 'yield.

EXAMPLE 3 V 1 i 24.3 parts of 5- fi-hydroxyethylsulfonyll -ben zoi az olone having a melting point of 184 C. are introduced at a ternperature ranging from 70 Cito 80 C. into'65jpar't1s' of sulfuric acid of 95% strength and the' te nperature is kept for). hours at C. to C. After cooling, the.

mixture is poured onto 200 parts of ice, and a'solution of 57 partsiof sodium carbonate'in185 parts by volum of Wateris then-added dropwise at a temperature ranging from 0 C." to 5 ;C. The whole isneutralize'd with about 15 "parts of calcium carbonate and then filtered ofi.

The filtrate contains 28.9 parts of 2-amin0phenol-4-flhydroxyethylsulfone sulfuric'acid ester which corresponds to 97.5% of the theoretical yield. v

EXAMPLE '4' 24.3 parts of 5-(,fi-hydroxyethylsulfonyl)-benioxaiolone are introduced, at a temperatureranging from 70' C. to

80 C., into 65 parts of sulfuric acid of 95% strength While cooling.

With acetoneand' ether and then dried under vacuo.

The crystalline product isolated in this manner amounts to 20, parts. -In the mother liquor there are'dissolved' further 8.8 parts of 2-aminopheno1-4-B hydroxyethylsul fone sulfun'c acid ester? The total yield, therefore 7 amounts to 97% of the theory; 1

We claim:

r 1. Process for preparing orthoraminophenol-fl-hydroxy-' V ethylsulfo'ne sulfuric acid-esters-Which comprisesheating 6 {3-hydroxyethylsulfonyl-ben.zoxazolones of the following 3. Process as claimed in claim 1, wherein 6-(,8-hydroxy formula ethylsulfonyl)-5-chloro-benzoxazolone of the formula NH-CO R l 5 01 SOz-CH -CHQOH SOa-CHaCHaOH is used as startin material. m which R g g abmember i i group 4 Process as Elaimed in claim 1 wherein 6-(fi-hydroxyconsisting 0 y rogen, romine, c orine, met y amino i a and nitro, with concentrated sulfuric acid of about 85% ethylsulfonyl) 5 methyl benzoxazolone of formula to 95% strength at a temperature between about 110 C. $13-00 and 160 C.

2. Process as claimed in claim 1, wherein 6-(fi-hydroxy- O ethylsulfonyl)-benzoxazo1one of the formula CH NH-O 0 S OaCH -CH1OH l is used as starting material.

References Cited in the file of this patent FOREIGN PATENTS 938,145 Germany Jan. 26, 1956 SOFGHTGHOH OTHER REFERENCES Scudi et al., Jour. Am. Chem. Soc., Vol. 63, p. 879 is used as starting material. (1941), QB 1 A5. 

1. PROCESS FOR THE PREPARING ORTHO-AMINOPHENOL-B-HYDROXYETHYLSULFONE SULFURIC ACID ESTERS WHICH COMPRISES HEATING B-HYDROXYETHYLSULFONYL-BENZOXAZOLONES OF THE FOLLOWING FORMULA 